


What You Don't Know

by DiNovia



Category: Supergirl (TV 2015)
Genre: Established Relationship, F/F, Superfamily
Language: English
Status: Completed
Published: 2019-12-25
Updated: 2019-12-25
Packaged: 2021-02-26 06:20:56
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,375
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21948733
Author URL: https://archiveofourown.org/users/DiNovia/pseuds/DiNovia
Summary: For the prompt:Kara and Cat have been dating for nearly a year. Eliza (or Alex) is visiting them in the Penthouse when Cat's mother Katherine stops by unannounced. Katherine has no clue they're together.
Relationships: Kara Danvers & Carter Grant, Kara Danvers/Cat Grant
Comments: 26
Kudos: 296
Collections: Super Santa Femslash 2019





	What You Don't Know

**Author's Note:**

  * For [Beryl4](https://archiveofourown.org/users/Beryl4/gifts).



It was like a dream, thought Kara, looking at the carefully-decorated tree in the corner of the great room where it could be seen equally well by guests arriving at the front door and by nosy neighbors across the canyon-like divide that was 12th Avenue. There were tastefully-wrapped presents under it but Kara knew those didn’t have anything real in them. She hadn’t put hers out yet - partly because it was still too early and partly because she had chosen wrapping paper featuring dancing penguins in ugly Christmas sweaters this year and it clashed with Cat’s blue and white theme in the worst way. 

Kara looked forward to the twitch the garish contrast would cause in Cat’s left eye but she knew better than to make it a week-long ordeal. 

Besides, everyone was on their best behavior this year because of Eliza.

Kara wasn’t quite sure how it had happened, exactly. One minute they were raising their glasses to toast Eliza’s extravagant Thanksgiving dinner at the farmhouse in Midvale and the next, she’d somehow secured an invitation to Cat’s penthouse for Christmas. Kara had only just moved in during the long, hot, tedious month of July when Cat had abruptly tired of the inconvenience of maintaining two households. Having Eliza join them for their first Christmas together seemed an unlikely happenstance, but Cat had insisted. 

A tiny, worrisome knot of concern in the back of Kara’s head wondered if what Cat really wanted was a buffer between herself and all the expectation and pressure usually surrounding the holidays, but she had yet to see any evidence of that. Eliza was only staying three nights and the first one had already gone off without a hitch. 

Tonight was Christmas Eve, though, and Kara knew enough about how quickly Cat’s moods could change to know that nothing was set in stone. She had long ago learned to keep a relatively low but useful percentage of her superhuman senses attuned to Cat at all times so that she could anticipate her needs. It had been a survival technique back then when she was just Cat’s assistant. Now that they were a couple, it was an invaluable source of support and caring that neither Kara nor Cat ever took for granted. 

Today had already been a full day. Last-minute hush-hush shopping trips and a decadent lunch at Amanda Frietag’s brand-new National City restaurant, _Ottimo_ , had them all feeling fat and happy. And, in Cat’s case, inspired. She decided on the spot they would stay in for supper that night and that she would cook. Which meant even _more_ shopping, this time for a couple of bottles of good wine and other bits and bobs she would need for the meal she was planning. 

Now that meal was ready and everyone was seated at the well-appointed formal dining table, somehow having managed to work up an appetite. Kara poured the wine as Cat appeared with the Salade Niçoise. She lifted her glass to offer a toast but froze before she could utter a single word, her grin sliding off her face as if it had been melted off with a blow torch. The rest of the table watched as Kara went white, then green, then white again.

“Darling?” “Kara, honey?”

Both Cat’s and Eliza’s voices had nearly identical tones of worry in them.

“She’s here,” said Kara. Well, not so much _said_ as whispered in horror.

“Who’s here?” asked Eliza, confusion making her frown. She looked from Kara to Cat just in time to see the CEO drop inelegantly into her chair, the serving bowl thunking against the table like a gavel.

“My mother,” said Cat morosely, covering her eyes briefly. Kara’s tone had left no doubt and she glanced up at her beautifully discombobulated superhero, hazel eyes meeting frantic blue. 

“There’s no time!” Kara squeaked as she threw her hands into the air, at a loss.

“What on Earth is going on?” asked Eliza, her confusion quickly becoming alarm.

Cat sighed. “My mother, the acerbic and impossible to please Katherine Grant, has apparently chosen tonight of all nights to stop by unannounced. She knows Kara is - _was_ my assistant but we haven’t had a chance to…”

Cat stopped and waved dismissively, unable to continue. Kara’s cheeks burned with embarrassment.

“She doesn’t know you’re together?” Eliza was aghast. “You’ve been dating my daughter for almost a year and you haven’t told _your own mother?_ ”

“Eliza--” The name came out strangled and harsh even as Kara’s eyes begged for help.

“How much time do we have?” Eliza tabled her annoyance for the moment, ideas whirling. 

“Twenty seconds?” said Kara, cocking her head. The elevator had just passed the fifth floor.

Eliza nodded. “You two follow my lead,” she said, pointing at the two women. “Carter, when I say the word ‘fumigating,’ I want you to scrunch up your face and say something about rats, okay?”

Carter giggled. “Sure thing, Eliza!”

The doorbell rang. 

“Kara, start serving dinner,” ordered Eliza. “Cat, you get the door. I’ll take care of the rest.”

Cat and Kara shared one last long and haunted look before doing as Eliza said. 

\---

Cat schooled her features toward blankness and took a deep, cleansing breath before reaching for the door.

The inimitable Katherine Grant stood in the hall in one of her many Ann Taylor pantsuits. Black, of course. Rare was the occasion her mother deemed appropriate for less funereal colors. 

“Mother?” she asked, feigning surprise at least until she saw the shopping bags Katherine carried, two in each hand. Real surprise overtook the false emotion when she saw they were stuffed with gaily-wrapped packages. “What are you doing here? I thought you loathed this time of year.”

Katherine leaned in for the obligatory air-kiss and brushed past Cat as she entered. 

“Usually I do but I was already out. Climate change benefit. Harrison is quite a passionate public speaker when he puts his mind to it.” Laughter filtered through from the dining room and Katherine craned her neck, affecting a look of shock. “Do you have guests, Kitty?” she asked, and Cat didn’t know whether to be offended by her mother’s apparent disbelief or proud that she’d caught her off guard.

“I do--” she began but Katherine had already left her behind, heading uninvited toward the source of the laughter. Cat, grim-faced, followed.

“--and he looked greener than the snake!” finished Eliza and laughter rang out anew until she noticed their audience. “Oh!” She stood. “Another guest…”

Carter saw the bags of gifts and couldn’t hide his own surprise. “Grandmother?” 

“Merry Christmas to you, too, Carter dear,” she said, sniffing with disapproval. 

Carter hurried to take his grandmother’s burdens from her, leaning up to give her an apologetic peck on the cheek. “Merry Christmas, Grandmother,” he said.

“Grandmother?” echoed Eliza, feigning dismay. “Mrs. Grant, it is so good to meet you!” She grasped Katherine’s hand warmly and looked behind her admonishingly. “Cat, we need to set another place at the table! You didn’t say your mother would be joining us.”

Unseen, Cat rolled her eyes. “It’s as much a surprise to me as it is to you,” she said, pulling a faint smile when her mother turned to look at her. “I’ll go get another place setting--” she began, but Katherine raised a gloved hand to stop her.

“No need, Kitty. I really can’t stay. Dinner plans, you know.” She looked down her nose at Eliza, adding, “But do introduce me to your guests.”

Cat steeled herself against her annoyance. How on point of her mother to drop by unannounced simply to leave immediately afterward, none the wiser to the chaos her little visits wrought.

“Katherine Grant, may I introduce Dr. Eliza Danvers. Eliza, this is my mother, Katherine Grant.”

“Danvers? Now, where do I know that name from?” Katherine tapped her cheek in time with the clock ticking in the hall. 

Kara took that as her cue and raised her hand, clearing her throat to get Katherine’s attention.

“From - er - me, Mrs. Grant?” she said, and her hand dropped to her side slowly as Katherine turned a baleful gaze her way. “She’s my - I mean, Eliza is my - um - foster mother.”

“And _you_ are?” she asked imperiously.

Kara’s eyes went wide behind her glasses. “I’m Keir - no - Kara - _Kara_ Danvers, Mrs. Grant.” She gestured at Cat weakly. “I - uh - I work with Cat.”

Katherine looked Kara up and down until recognition finally dawned. 

“Kitty, why are your assistant--” She turned to encompass Eliza in her question. “--and her foster mother your guests at dinner on Christmas Eve?”

Eliza chuckled. “Well, it’s funny you should ask--” she began, but Katherine raised her hand again. 

“I wasn’t asking you,” she said, though not unkindly, and Eliza thought she saw something akin to mirth glint in Katherine’s eyes as she turned to look at Cat. “This is my daughter’s question to answer.”

Cat closed her eyes, then shook her head, letting a smile - a real one - curve her lips upward when she opened them again. 

“First of all, Kara’s no longer my assistant,” she said. “I promoted her and gave her her own office last year. Now she’s wowing Snapper Carr from the Tribune’s local interest desk.”

Katherine harrumphed. “Doubtful,” she said. “Not that you’ve been promoted, dear.” She directed that comment to Kara. “But wowing Snapper? Impossible. Nothing impresses him. Had he been an eyewitness at the birth of Christ, his sole comment would have been something disparaging about the state of the manger.” She turned back to Cat. “Go on,” she urged.

“Second, strictly speaking, only Eliza is our guest.” Cat reached out her hand and Kara rushed to take it, tucking herself into Cat’s side, blue eyes somehow both worried and wide with wonder. She couldn’t stop her grin so she didn’t even try.

“Because?” Though her tone was sarcastic, Katherine’s gaze was curious.

Cat looked her mother square in the eye and tossed her head defiantly. “Because Kara and I have been dating since last Christmas,” she said tightly, daring her mother to say one untoward word. “After I’d had one too many terrible hair days due to the inadequate air conditioning at her loft this past July, I invited her to move in with us. Luckily for me, she agreed.”

She glanced up into Kara’s eyes just for a second, but that was enough. Everything about Cat softened at that moment and she reached up to cup Kara’s cheek in her palm.

“I’m in love with her,” she whispered, and the light of that love filled her hazel eyes to overflowing.

Kara tightened her grip on Cat’s hand and continued to beam in an increasingly ‘Sunny’ Danvers way. 

Katherine simply nodded.

“Good,” she said, opening her Prada bag to retrieve her iPhone. “Now,” she added, winking saucily at Cat when her daughter was finally able to tear her eyes away from the younger woman, “was that really so hard?”

Eliza snorted and Carter clapped his hands over his mouth to keep from laughing out loud.

Kara’s eyes went wide with unadulterated shock. She opened her mouth to say something, but only managed “Wha--?”

Cat, on the other hand, looked as if she could spit nails. “You knew?” Her eyes darkened suddenly and Eliza thought she might stamp her foot. “You _knew_ and you let me stand there like a child, thinking you--”

“I let you stand there and tell me about your new relationship and living arrangements like an adult,” said Katherine airily. “Something you were apparently unable to do. Now pick your jaw up off the floor, Kitty darling, and walk me to the door. I’m going to be late for my dinner as it is and Idina, though forgiving, won’t wait forever.”

What could Cat do but obey? She kissed Kara first, though, just to be on the safe side.

“Merry Christmas, Carter,” Katherine said to her grandson. “Merry Christmas, Dr. Danvers. I do hope we get to chat at length at some future date. I have a million questions about your last paper on synthetic polymers and covalent bonding.”

Now it was Eliza’s turn to pick _her_ jaw off the floor. “Merry Christmas,” was all she could think of to say.

Katherine turned to Kara, who was gaping at her unapologetically. “Kara - though this shouldn’t matter to either of you - I approve. You’ve brought out the best in my daughter but you’ve also proven you can handle her worst. All I ask is that you take care of my grandson as well as you take care of her.”

“I promise,” vowed Kara and it was exactly that: a solemn vow. Everyone in the room was certain of it.

Katherine nodded again. “Come give me a kiss goodbye, Carter, and I’ll be on my way.”

Carter ran to Katherine’s side and did as she’d asked, adding an impulsive hug around the neck for good measure. 

Cat escorted her mother to the door but held it closed for a moment.

“I have one question,” she said.

Katherine’s eyebrows shot upward. “Only one, darling?”

Cat ignored the sarcasm and asked, “Who told you?”

Katherine chuckled. “Let’s just say those monthly phone calls you force Carter to make to me can be quite enlightening. Especially when he’s excited _and_ distracted at the same time.” She shook her head, remembering the call as if it had only been yesterday. “I don’t even think he realized what he’d said but it was the happiest I have ever heard him. Putting two and two together wasn’t hard after that.”

Based upon Cat's blank look, that explanation clearly wasn’t enough.

“It was mundane, really. It wasn’t so much what he said but the _way_ he said it.” Katherine squeezed Cat’s arm. “I’d asked if you had dinner plans for his birthday and he said ‘I don’t know. Kara will probably stop to get pizza on her way home.’”

Cat tried to keep herself from getting misty-eyed but failed, shaking her head instead. She opened the door and Katherine took one step through it before turning back.

“Love looks good on you,” she said quietly. “Merry Christmas, Cat.” 

“Merry Christmas, Mom,” whispered Cat in return, but Katherine was already gone.

_fin_

**Author's Note:**

> As a general rule, I have found the character of Katherine Grant to be a difficult one to write only because she will not do as she is told. I had planned this story to be very different, but this is the story Katherine wanted to tell. 
> 
> I would also like to dedicate this to my wife, Lisaof9, who has been very patient with me this week. It's been a doozy and I have not been the most fun to be around. Thank you, my love.


End file.
